Abstract:The research of the characteristics of rock and soil erosion was conducted on the dumpling platform and slope with the method of artificial rainfall and on the basis of analyzing the diameter-level of the selected spoil and residue particles in Jin'anqiao hydropower station,and the result showed that:(1) After removing the stones of which the particle diameter>2 cm,the percentage of spoil particle diameter>4 mm was 48.42%,which was 13.64 percent point more than the original landscape surface.In original landscape surface,the percentage of the particle diameter<0.25 mm was 15.81%,which was just 8.56% in the spoil particles.(2) In one rainfall process,the largest runoff was in dumpling platform,which is 2.27 times of the original grassland;and the smallest runoff was in the dumpling slope,which is 45.5% of the original grassland.(3) In one rainfall process,the initial sediment of both the dumpling platform and slope were lower than the original grassland of poor vegetation;when it archived stable sediment,the sediment of dumpling slope was close to the sediment of original grassland,and the sediment of the dumpling platform was much lower than the sediment of original grassland.(4) In one rainfall process,in the same period the grassland had the largest total sediment,followed by the dumpling platform,and the dumpling slope had the lowest sediment.(5) In the process of rock and soil erosion,the runoff amount and sediment yield had significant power function relations.

Abstract:Through field trials of three-stubble vegetable in one year,7 different kinds of fertilization modes(i.e.Applying none fertilizer,Chemical fertilizer applied as base manure,Chemical fertilizer applied half as base manure and half as additional one,Chemical fertilizer and dicyandiamide applied as base manure,Chemical fertilizer and dicyandiamide applied half as base manure and half as additional one,Applying chemical fertilizer and organic manure,Applying organic manure.) were conducted to tested the effects of using different kinds of fertilization modes on yield and nitrate's content of vegetable,and loss of nitrogen and phosphorus in vegetable field.Results showed that: Used two kinds of fertilization modes,such as "Applying chemical fertilizer and organic manure" and "Chemical fertilizer and dicyandiamide applied as base manure",not only relatively higher output and lower nitrate's content of vegetable could be gained,but also the lost amount of nitrate-nitrogen,ammonia-nitrogen and water-solubility phosphorus,which were carried by ground runoff from vegetable field during the session of planting,was obviously reduced.Consequently,Non-point Source Pollution from Agriculture resulting from vegetable field was cut down.Therefore,those two kinds of fertilization modes are worth of being popularized on vegetable production in the future.

Abstract:为了探明小区内不同坡度和种植模式对径流污染的影响,以寻求适合坡地条件下控制径流污染的有效途径,通过径流小区监测和径流污染物浓度测定,并结合污染负荷估算法和水污染综合指数法评价径流污染的差异,结果表明,坡度对总氮、总磷、COD以及泥沙在径流中的浓度有一定的影响,在相同种植模式条件下,25°小区中产生的各个径流污染物浓度都明显高于15°小区,而径流污染物浓度在不同种植模式下浓度大小依次为,坡改梯 经果林>玉米 红苕>豆角 红苕>经果林幼林,而通过采用降低坡度和坡改梯结合种植经果林的治理措施,将水土保持工程措施和农业措施相结合,对抑制径流污染有较好的作用。

Abstract:It was the fundamental purpose of controlling agriculture no-point pollution to reveal the mechanism of substrate soil solute transported in runoff.To analyze the hydraulic characteristics of overland flow and parameters of soil solute in runoff,the Hydro-dynamic properties of soil solute in runoff on different loess slope was studied in this paper.The aim of study was to go deep into understanding the mechanism of soil solute transference in runoff.The result showed that the quantity of soil solute in runoff had relation to the ratio of roughness coefficient to averaged flow depth on different loess slope.The mean concentration of soil bromide in runoff,the average losses rate of soil bromide in runoff and the relative losses of soil bromide in runoff each of them decreased as the ratio of roughness coefficient to averaged flow depth increased.Both the data for the average losses rate of soil bromide in runoff and the relative losses of soil bromide in runoff to the ratio of roughness coefficient to average flow depth(n/h) respectively fit the form of an exponential curve under the different loess slope.

Abstract:Under the condition of indoor artificial rainfall simulation,experiments are carried out regarding rainfall intensity,rainfall duration during different seasons in two soil ditches planted with Caragana korshinskii and Elymus dahuricus and one bare dirt ditch.It is concluded that after planting Caragana korshinskii and Elymus dahuricus,the rainfall runoff yield,runoff duration and runoff transformation rate are in an increasing order,that is: Caragana korshinskiiCaragana korshinskii>Elymus dahuricus.The testing results will be used for analyzing hydrographic effect of herbs and shrubs and evaluating performance of slope protection,besides,the result will be helpful to establish measures to prevent water loss and soil erosion,and superficial layer geological disasters such as landslide,debris flows.

Abstract:Farming system is an important way to affect the ecological environment in the ecotone between agriculture and animal husbandry of north China,and the irrational farming system has made the local environment deteriorated.Characteristics of soil physical properties change,including wind speed,soil tightness,soil organic matter,soil moisture,soil roughness,the ratio of vegetation coverage,and so on,were studied under different farming systems,including abandoning cropping system,fallow cropping system,rotational cropping system,and conservation cropping system with Wuchan county as case study.The result showed that different farming system had obvious influence on wind speed,soil tightness,soil organic matter,soil moisture,soil roughness,the ratio of vegetation coverage and the mass of wind erosion,and the conservation cropping system could decrease soil erosion obviously and prevent land desertification effectively.The conservation cropping system should be extended in order to promote the sustainable development of agricultural production in the ecotone between agriculture and animal husbandry.

Abstract:以广州流溪河流域内土地利用类型齐全、相对闭合的小流域——新田小流域为例,分析了不同暴雨径流过程与土地利用对氮、磷流失的影响,结果表明:(1)林地氮磷的流失较少,说明植被覆盖可以有效减少土壤侵蚀、总磷和总氮的流失;而坡耕地是氮磷流失的重要策源地,说明人类活动对土壤氮磷的干扰很大。(2)流域径流中氮、磷的流失形态分为可溶态和颗粒态,径流中流失是以颗粒态形式流失,即氮磷是以泥沙结合形式流失的;径流中氮素主要是以可溶态氮流失的。(3)氮磷浓度在降雨初期与末期最大。(4)降雨径流是引起土壤氮磷损失的重要原因,但不同的土地利用方式是造成土壤氮磷流失的本质因素,因此在降雨前应特别注意减少和避免那些会加剧土壤侵蚀和磷流失的农事活动。

Abstract:One field experiment was conducted in the yellow Chinese chive production system on north bank of Dianchi Lake to investigate the effects of reducing amount of nitrogen fertilizer and the application of Dicyandiamide(DCD)on losses of nitrogen from the vegetable field.Results indicated that the treatment of decrease of N by 20% reduced the TN content of leaching,lateral leaching and runoff by 37.0%,22.2% and 28.9% respectively;the treatment also reduced the nitrate content of yellow Chinese chive by 13.6% and had no obviously effect on its yield.The application of DCD on the base of reducing nitrogen reduced the TN content of leaching,lateral leaching and runoff by 58.4%,59.7% and 17.1% respectively.While it increased the yield of yellow Chinese chive by 8.7% and reduced its nitrate content by 24.8%.Therefore,reducing the amount of nitrogen fertilizer and applying DCD may be important measures to reduce nitrogen losses from the Yellow Chinese Chive fields and reduce the nitrate content of yellow Chinese chive.The technique would have important practical significance and be of good popularization value.in the study area.

Abstract:The pattern of soil nutrient loss from slope land was studied in Three Gorges Reservoir Area by means of simulated rainfall equipment.For purple soil and terra gialla soil,the nutrient content of surface soil of slope land declined and the declining extent of surface soil was increasing with rainfall intensities increasing,but the nutrient content of runoff and sediment was irrelative to rainfall intensities.The nutrient content of runoff was lower than that of sediment,but the discrepancy was mainly lied in the total nutrient and the discrepancy of the available nutrient was slight.For nutrient loss from slope land in Three Gorges Reservoir Area,the nutrient loss form purple soil was mainly caused by sediment,but that form terra gialla soil was caused by runoff and sediment.

Abstract:通过黄土坡面的冲刷试验,研究了不同立地条件、坡度、流量条件下坡面的侵蚀特征及坡面入渗与侵蚀的关系,研究结果表明,在其它条件相同时,裸坡的侵蚀量分别是草被覆盖度为30%,80%坡面的4倍和20倍;80%草被覆盖度坡面的稳定入渗率为30%覆盖度坡面的2倍,是裸坡的9倍;10°坡面的侵蚀产沙量只有20°,30°坡面的1/10;20°,30°坡面的入渗率约是10°坡面的1/10;1 L/min流量下的相对稳定侵蚀量是5 L/min和7.5 L/min流量的1%左右,而3 L/min的稳定侵蚀量则为后者的20%左右;在不同的流量条件下,坡面侵蚀量随入渗率的增加呈线性减少,两者之间有很好的相关性。

Abstract:The contents of five nutrient elements(K,Ca,Mg,Mn,Fe) in through-fall,stem-flow were measured in the Pinus koraiensis virgin forest of Xiaoxing'an Mountains,and according to the allotment of water amount,net input-quantity of each element in the forest was calculated,the results showed that:(1)The contents of nutrient elements in precipitation,through-fall,and stem-flow were all had the decreased order of stem-flow>through-fall>precipitation except of Fe.The average contents of different nutrient elements were in the decreased tendency of Ca>K>Mg>Mn>Fe.(2)The biggest coefficient of variation(Cv) in precipitation was 1.514 for K element and the least one was 0.827 for Ca element.The biggest Cv of nutrient elements in through-fall,stem-flow of the Pinus koraiensis virgin forest were Mn,Mg,and Fe,and the least were Ca,Mn.The average contents of the five nutrient elements' Cv in precipitation,through-fall,and stem-flow had the decreased tendency of precipitation > through-fall > stem-flow.(3)The net input-quantity of nutrient elements in the Pinus koraiensis virgin forest was as follows:K>Ca>Mg>Mn>Fe,furthermore,the net input-quantity of Fe in Pinus koraiensis virgin forest was negative.

Abstract:采用实地调查与田间模拟实验相结合的方法,研究了滇池流域沿湖15个乡镇农田地表径流氮、磷流失状况及其影响因素。结果表明,研究区农田地表径流氮、磷污染负荷很高,年均流失量差异较大,总氮为5.07~113.16 kg/hm2,总磷为0.15~10.14 kg/hm2。高强度的化肥施用是造成农田径流氮、磷流失量大的主要原因,同时也与土地利用方式、水肥管理方式及种植制度有关;不同坡度农田径流中氮、磷的输出量不同,从6°~12°氮、磷流失急剧增大,12°以后流失量增加减缓;无论在一次降雨中,还是在作物生长周期内,径流中氮、磷流失速率均表现出随时间参数增加而递减的趋势;施肥处理不同,氮、磷流失量存在一定差异,其中尿素与普钙配合施用可减少氮、磷流失,同时获得较高的白菜产量。

Abstract:以1995年、2000年遥感土壤侵蚀调查(RS)资料为基础,结合2005年实地调查资料,研究岷江流域土壤侵蚀的演变规律,应用马尔柯夫模型对流域土壤侵蚀的发展趋势进行预测,同时探讨岷江流域水土流失治理分区与对策。结果表明:(1)岷江流域土壤侵蚀现状表现为:侵蚀总面积19 907.7 km2,占幅员面积的43.77%;侵蚀类型以水蚀为主,占侵蚀面积的88.24%;侵蚀等级以中度侵蚀为主,占侵蚀面积的44.07%。与1995年相比,土壤侵蚀面积减少369.6 km2,减少比例为0.81%。计算表明岷江流域2000年土壤侵蚀量为8.94×107t,平均侵蚀模数1 966 t/(km2.a)。(2)应用Markov模型对2005-2025年岷江流域土壤侵蚀面积的预测结果显示:岷江流域土壤侵蚀面积将呈逐年减少趋势。到2025年,土壤侵蚀面积将比2000年减少1 452.87 km2;未来20年内土壤侵蚀量每5 a以3.17×107t的速度减少。(3)岷江流域水土流失治理应在以全流域综合治理为目标,在科学规划基础上,选择优先治理区和重点治理区,以不同类型的治理工程为主要途径,推动岷江流域水土流失的有效治理。

Abstract:流动沙地采取不同治理措施7 a后,天然植被恢复效果不同。①生态垫阻断了天然植被的正常演替规律,植被盖度和物种丰富度只有4.31%和3种。同期营造的人工林中,小叶锦鸡儿和侧柏林地的植被盖度和物种丰富度最高,均大大超过同期封育的流动沙地,新疆杨和欧美杨84林地的植被盖度和物种丰富度最低,沙枣和榆树林地居于中间位置。②新疆杨和欧美杨84林地植被一年生草本占绝对优势,榆树和沙枣林地多年生草本和灌木数量有所增加,侧柏和小叶锦鸡儿林地物种生活型结构已趋于多样化。③集沙观测表明,生态垫、侧柏和小叶锦鸡儿林地均无风蚀现象,欧美杨84和新疆杨林地风蚀较为严重,榆树和沙枣林地风蚀较轻。

Abstract:A study on soil and water conservation effects of different introduced grasses in dry-hot valley was conducted in Yunnan.It includes analysis of biomass,fresh weight and water holding capacity of leaves and stems,litter weights and water holding capacity,soil bulk density,soil porosity,soil moisture content,capillary moisture capacity,saturation moisture content,soil constitution and organic matter,soil permeability and erosion-resisting characteristics.The results showed that water holding capacity and soil improvement of three introduced grasses is Setaria sphacelata cv.Narok>Pennisetum clandestinum cv.Whitte>Trifolium semipilosum cv.Safari.Setaria sphacelata cv.Narok is the best fodder and has the highest water holding capacity and soil improvement in three grasses.Pennisetum clandestinum cv.Whitte is the second.They can be planted in Yunnan.

Abstract:Vegetation is one of the important factors affecting soil and water loss,thus is regarded as one of the key parameters of soil erosion prediction.It's well known that the vertical structure of vegetation is composed of different layers and each layer has different impact on soil erosion,yet the traditional coverage cannot reflect the impact of different layers on soil erosion,and sometimes overestimate or underestimate the impact of vegetation on soil erosion.With the consideration of this fact,a new vegetation factor index Cs,structured vegetation factor index,was proposed and the vegetation index factor models have been established using multiple regressions in this paper.The case study in the locust tree and the Chinese pine communities showed that tree layer,herb layer and litter layer are important to prevent the soil erosion and their weights are 0.0150,0.591,0.394 and 0.0608,0.828,0.112 respectively for the Chinese pine and the aspen communities.Structured vegetation factor index,which considering the relative roles and coverage of each layer in the vegetation communities,could be better than traditional coverage in describing the relationship between vegetation and soil erosion.This could be an idealized indicator and have great significance for both soil erosion evaluation and prediction and the vegetation constructions for soil and water conservation.

Abstract:It is vital to solution of water resource's crises to effectively utilize surface runoff.Based on data of land use,soil and rainfall,runoff in hilly regions of Sichuan basin at a local scale was calculated and analyzed as a sample of Bashan town in Zhong County.The results showed that: firstly,the spatial distribution of runoff was highly related with land use type and agro-type on the surface,and amount of runoff on water area or un-utilized land was larger than those on paddy field and dry land with crop growing.Secondly,runoff was mainly distributed in April to October,being more than 90% of the annual total runoff,and the annual change of runoff was similar to rainfall.Thirdly,the runoff was unevenly distributed with high and low flow year by turns and its small value of Cv.The SCS model was a simple and practical runoff computation method with a few parameters,in which the relationship among soil characteristics,land use status,and runoff was substantially considered.And the data of local runoff have been become more simple and visual by using the GIS software.Therefore,runoff space-time change on each catchment analyzed by using the GIS could provide an effective methods and adequate references for the allocation to agricultural water at a local scale.

Abstract:以GIS为平台,结合第2次遥感调查黄土高原土壤侵蚀数据库,对大理河流域土壤侵蚀空间分布的地貌特征进行了研究。结果表明:水力侵蚀是大理河流域土壤侵蚀的主要形式。各种强度水力侵蚀空间分布的高程特征呈现峰值现象,其中强度以上水力侵蚀面积集中分布于1 240 m高程左右。各种强度水力侵蚀的面积比重,随着坡度的增加呈现先增大后减小的趋势,25°左右存在一个侵蚀临界坡度。临界坡度值随着侵蚀强度的增强而增大。坡向特征呈现双峰现象,其中东北与西南坡向是大理河流域的优势坡向,强度以上水力侵蚀在东北坡向的分布比重大于西南坡向。大理河流域土壤侵蚀存在一个30 m左右临界起伏度。土壤侵蚀强度的变化对起伏度的变化不敏感。此结论为进一步研究流域水土流失动态模拟与区域生态环境长期演变提供了新思路和新角度。

Abstract:For an ecological protection of guest-earth spraying carried on a typical rocky slope located at Ji-Qing south expressway,semi-arid area of Shandong province,a series of testing results could be acquired by testing and analyzing on nutrient components of the spraying-earth such as contents of organic matter.It has been found by analyzing these results that the contents of the available organic matter and nitrogen decay with the time in the various extents.The content of the nitrogen trends to stabilize after four months,whereas one of organic matter don't stop decaying yet for half a year,from which the longer restoring time can be judged.Due to the difference of the attenuation mechanism,both the turning point and the time effect of them are no-cooperative.It can be predicted that with the decay of the leaves and bark coming from slope vegetation,both the nutrient supply of vegetation by itself and the restoring of spraying earth nutrient components may be realized in the future.These studies have practical significance for developing vegetation restoring technology on the poor soil and rocky slope ecological protection.

Abstract:The feature of the nutrient cycle and balance of the six primary strip lands were studied by investigating the input and output nutrients of the six patterns in Xingdian irrigation district.The results indicated that N,P and K cycle of the five planting patterns were good with the exception of nitrogen deficiency of wheat/soybean strip field,but the only balance condition was adequate manure input and symbiotic nitrogen-fixing of legume crops.Manure provided 4.62%~8.93% N,17.34%~22.31% P and 72.61%~82.07% K of total nutrients.Legume crops provided 14.08%~42.45% N of total nitrogen.The amount of N and P coming from fertilizers occupied 52.27%~76.06% and 61.40%~70.91% of total N and P,respectively.There were 8.35%~12.04% N,3.72%~7.74% P and 9.20%~17.48% K of total nutrients input to the strip lands ecosystem by rainfall and irrigation.The proportion of N,P,K input,observing from the structure of fertilization,were extremely unreasonable in all the six planting patterns.The countermeasure should be carried out to control the application amount of N and to increase the application rate of K.Meanwhile,the application of fertilizer K should be focused on.The technique to return crop straw into farmland and harvest in high stubble should be extended to increase the nutrient recycle and reuse efficiency.

Abstract:Time-space effect of soil nutrient and chemical characteristics of Robinia pseudoacia L.plantation forestland in Loess Plateau has been studied.The results shows that: soil organic matter,pH,total N,available N,available P and available K,exchangeable Ca and exchangeable base capacity changes irregularly with tree age,total P and exchangeable Mg changes fluctuantly;Soil organic matter,total N,available N decreases by power function with soil depth,available P tends to decreases,total P,available K,exchangeable Ca,exchangeable Mg and exchangeable base capacity varies irregularly with soil depth,but pH-value changes fluctuantly;Compared with wasteland,soil organic matter,total N,available N,total P,available P,exchangeable Ca,exchangeable Mg and exchangeable base capacity raises respectively by 21.56%~96.8%,34.3%~160.1%,191.5%~238.4%,2.1%~24.1%,19.82%~92.71%,64.21%~80.02%,25%~46.5%,67.2%~89.5%.These showed that Robinia pseudoacia L.plantation can improve the condition of soil nutrient effectively.

Abstract:The effect of long-term fertilizer on total P,valid P,year-and-profile P composition,the property of P absorption and desorption of the soil,the index of P requirement of the soil,and so on,were studied,with the soil treated by CK,N,NPK,NPKM,NPKS,M in the long-term fertility-assessed experiment.The results showed that: both the long-term application of chemical phosphate and chemical fertilizer plus organic fertilizer can heighten the amount of total P,valid P.In treatments applied with organic fertilizer only and chemical fertilizer plus organic fertilizer,the accumulation of Ca-P and Al-P was the main form of P composition changing in soil,chemical phosphate can increase the content of total P in soil,the increasing-range of Al-P were the most in inorganic P composition,the O-P of soil was stable relatively in all treatments.With the time extending,the increasing of higher-validity Ca-P,Al-P became the trait of P composition changing.The effect of applying on topsoil was the most,and on deep soil relatively weaker,long-term application of phosphate and organic fertilizer can prompt P moving to substratum and increase P content in the deep soil.The strength of soil absorbing external P in treatments of NPKM,M was lower obviously than that in treatments of NPK,NPKS,CK and N,organic fertilizer can advance the reusing of P-absorbed,there was 47.72% P-desorbed in P-absorbed in the treatment NPKM,42.89% in M,and less than 8% in CK,N,NPK and NPKS.The PFI of treatments MNPK and M respectively was 2.51 and 2.69,obviously less than 4.53 and 4.37 of treatments N and NP.

Abstract:Low phosphate availability is one of the major limitations to crop production.Organic acids are a principal component of root exudates and have been hypothesized by many authors to be involved in the mobilization of nutrients within the rhizosphere.Mobilization of insoluble phosphates by root exudates plays an important role in improving P nutrition of crops.The effect of different phosphorus level on dynamic of available phophorus in soils had been studied.At the same time,two maize inbred lines with different tolerance to low-P stress were grown for 15 days in nutrient solution with different phosphorus treatment.The root exudates were collected and added into the three types of soil which had incubated for 95 days.The results showed that the available phosphorus content quickly increased by application of different phsphate,and then constantly decreased by time,and were steady after 60 day;and the available phosphorus from acid soil is significant lower than alkali soil and neutral soil.The soil available phosphorus content was extracted by the root exudates of M02 collected under low phosphorus condition significant pronounced with the addition of insoluble phosphate to the deionized soil;and AlPO4 mobilization by root exudates was significantly higher than Ca3(PO4)2.

Abstract:不同钾、镁浓度及摩尔比供应对大田及温室土壤K ,Mg2 离子吸附特性影响的研究结果表明:大田及温室土壤对K ,Mg2 离子的吸附量均随其供应浓度和比例的增加而增加,日光温室栽培下土壤对K 的吸附量显著小于大田土壤;K /Mg2 为2∶1时不同土壤对Mg2 离子吸附量的差异均较小,K /Mg2 为1∶1时,温室塿土Mg2 的吸附量低于大田土壤,而潮土温室和相应大田土壤间的差异较小;随供应的K 浓度和比例升高,土壤对Mg2 离子的吸附量显著降低。随K ,Mg2 离子浓度提高,大田土壤K 吸附率均呈对数趋势下降,而温室土壤K 吸附率呈对数趋势增加;不同K /Mg2 对大田土壤K 吸附率影响较小,而温室土壤在K /Mg2 大时K 吸附率较大;不同土壤对Mg2 的吸附率随K ,Mg2 离子浓度变化未表现明显的规律性。随着K ,Mg2 离子总浓度的增加,土壤中Ca2 离子的解析量呈直线增加,不同K /Mg2 对Ca2 离子解析量影响的差异较小,温室土壤Ca2 离子解析量大于大田土壤。

Abstract:Based on the long-time location exeriments,accumulation and distribution of available sulfur in soil of different cropping systerms under the condition of 22 years' continuous application of NP chemical fertilizer in Loess Plateau were studied.The results showed that there are two peaks of available sulfur in soil profiles.The first peak occurred in 60-80 cm soil depth with the values of 27.07 mg/kg,25.42 mg/kg,24.23 mg/kg,22.61 mg/kg,16.56 mg/kg and 15.14 mg/kg in maize-wheat(2 a) millet rotation,pea-wheat(2 a) millet rotation,wheat(2 a) millet-maize rotation,pea-wheat(2 a) maize rotation,wheat succession and sainfoin-wheat(2 a) rotation respectively.The second peak occurred in 120-180 cm soil depth and the values in maize-wheat(2 a) millet rotation,pea-wheat(2 a) millet rotation,pea-wheat(2 a) maize rotation,sainfoin-wheat(2 a) rotation,pea-wheat(2 a) maize rotation and wheat succession were 34.20 mg/kg,32.16 mg/kg,31.00 mg/kg,30.32 mg/kg,29.16 mg/kg and 26.22 mg/kg,respectively,which were higher than the first available sulfur peak value.The accumulation of available sulfur in soil profiles(0-200 cm) in maize-wheat(2 a) millet rotation,wheat(2 a) millet-maize rotation,pea-wheat(2 a) millet rotation,pea-wheat(2 a) maize rotation,wheat succession and sainfoin-wheat(2 a) rotation were 559.64 kg/hm2,538.88 kg/hm2 514.34 kg/hm2,489.58 kg/hm2,432.75 kg/hm2 and 423.68 kg/hm2,respectively.The results also showed that long-time application of P fertilizer was the principal factor influencing the distribution of available sulfur in soil profile at different cropping systerms.Additionally,available sulfur transported to deep soils in this study.The results suggest that the difference of sulfur uptake and utilization caused by different crops and cropping styles had effected accumulation and distribution of available sulfur in soil profiles.

Abstract:以喀斯特地区不同退化程度的两个典型坡地为研究对象,通过测定土壤部分属性与土壤有机碳含量的空间分布特征和δ13值,探讨土壤侵蚀和沉积过程中土壤有机碳(SOC)动态变化及影响因素。结果显示:自然坡地的表层土壤有机碳含量较高(6.3%~16.2%),δ13C值随着坡面向下逐渐降低,范围在-21.7‰~-14.3‰之间,变幅较大;撂荒坡地表层土壤有机碳含量为4.4%~7.4%,δ13C值在-21.4‰~-20.3‰之间,变幅相对较小。表明自然坡地沉积的新有机质要高于撂荒坡地,且两者δ13C值均与地表植被种类显著相关。另外,两个坡地各个地形部位的剖面土壤有机碳含量和δ13C值随深度变化,反映了植物残体的输入及在土壤中分解累积特征,有助于了解坡地土壤成土过程和受到的侵蚀程度。

Abstract:At the south edge of the Tengger Desert,chose the moving dune,enclosure for 5 years,enclosure for 15 years and enclosure for 25 years of the restoration successive series,It represents the different stages of reversion process of desertification.The soil chemical properties of the decertified land were studied in reversion process of desertification with the method of substituting time with space.The results showed that the soil pH,soil electrical conductivity,soil available potassiumat,soil available phosphorus,soil total nitrogen and soil organic matter showed varying degrees of fluctuation changes at depth of 0-300 cm,but the mean valuehave increased continuously.Surface-soil pH gradually decreased in reversion process of desertification,but surface-soil electrical conductivity and soil fertility on behalf of soil available potassiumat,soil available phosphorus,soil total nitrogen and soil organic matter gradually increased in reversion process of desertification,and the overall difference of the surface soil chemical properties in various stages was significant.It is concluded that the soil chemical properties gradually develop in the benign direction in reversion process of desertification at the south edge of the Tengger Desert.

Abstract:Coastal wetlands are sensitive to global climate change and may play an important role in the global carbon cycle.However,the dynamics of carbon cycling in coastal wetlands and its response to LUCC is still poorly understood.In this study,the influence of LUCC from native reed wetland to tidal aquaculture land,paddy field,grassland,abandoned land and pond aquaculture land on sediment or soil(0-50 cm) organic carbon and labile soil organic carbon(LSC) concentration was investigated in the wetland of Min River estuary.The results showed that the concentration of SOC in 0-50 cm soil layer under tidal aquaculture land,paddy field,pond aquaculture land,grassland and abandoned land was 27%,75%,67%,1%,60% lower than that under native reed wetland,respectively.When native reed wetland was converted to tidal aquaculture land,paddy field,pond aquaculture land and abandoned land,the SOC stocks decreased by 11%,50%,37% and 24%,but when native reed wetland was converted to grassland SOC stocks was increased by 44%.The decreasing magnitude of SOC concentration and SOC stocks with soil profile depth under grassland was greater than native reed wetland.Vertical distribution characteristic of SOC concentration and SOC stocks under paddy field was not distinctness;the SOC concentration(0-30 cm layer) increased when paddy field was abandoned,Vertical distribution characteristic of SOC concentration was distinctness.In general,the difference in LSC among the different land use types and changes with depth were greater for the SOC concentration.The concentration of LSC under tidal aquaculture land,paddy field,pond aquaculture land and grassland was 24%,83%,84%,42% lower than that under native reed wetland,respectively.The concentration of LSC was increased by 47% when paddy field was abandoned.

Abstract:通过盆栽试验,初步研究了种植黑木耳后的下脚料(即菌糠)对苏打盐碱土的改良作用。结果表明:黑木耳菌糠施入苏打盐碱土后,土壤理化性状发生了显著改善;随菌糠用量的增加,其物理性质主要表现为:土壤团聚能力增强;土壤田间持水能力增强;其化学性质表现为:土壤pH值随菌糠用量的增加而降低,土壤可溶盐组成中CO32-和HCO3-的含量随菌糠用量增加而减少,当菌糠用量达50.0 g/kg时,CO32-消失;Cl-,SO42-含量同全盐量的变化规律一致,随菌糠用量的增加而提高;其可溶盐中Ca2 ,Mg2 ,K 、Na 含量增加。而土壤交换性阳离子组成中Ca2 ,Mg2 含量增加,交换性Na 含量降低,阳离子交换量增加,其碱化度降低。且交换性Ca2 ,Mg2 含量与菌糠用量成正相关关系;交换性Na 含量、碱化度与菌糠用量成负相关关系。即黑木耳菌糠施入苏打盐碱土后,改善其理化性状,创造了宜于作物生长的土壤环境。施用菌糠提高了土壤肥力,在施入菌糠的苏打盐碱土上种植牧草,提高其地上部生物量。菌糠作为有机改良剂改良苏打盐碱土是可行的。

Abstract:The research is conducted in the substrate amendment of coal-gangue pile in Jixi Coal Mine with the soil from tailrace dredging in the local rivers and coal ash from the generation plant as the soil amendment.After the amendment,the average pH value of substrate has deduced to 6.90 compared with the control pH value of 8.26;the saturated water content increases by 59.84%;water holding span has prolonged by eleven and a half days;available nitrogen content reaches 316.05 mg/kg,4.38 times higher than that of the control;available phosphorus content reaches 24.224 mg/kg,43.53 times higher than that of the control,which greatly motivate the growth of height,ground diameter growth and crown diameter growth of Ulmus pumila L.,Amorpha fruticosa L.,and Medicago sativa L.Statistics and experimental result show that mixed application of tailrace dredging and coal ash from the generation plant has significant amending effects on the substrate.It is an effective access to conducting the substrate amendment to coal-gangue piles and also one of the best ways to reutilize the solid waste disposal rationally.

Abstract:The rule of plant nutrient absorption can help us to take effectively measure to regulate plant growth and to increase grain yield.A research of different N-fertilization rates on dry matter accumulation and the changes of nitrogen absorption was conducted on the bases of long-term positional fertilization experiment on dry highland of the Loess Plateau,and the results showed that the dry matter accumulation changed as a "S" curve during the whole growth period,and the dry matter accumulation of winter wheat was increased with the increasing of N-fertilizer amount,the accumulation rate showed clearly a single-peak curve,the fast rate of dry matter accumulation was found in the jointing-filling stage.N content of wheat plant and the accumulation of N nutrient were increasing with the increasing of N-fertilizer amount,two key periods of N accumulation were found in the before winter-jointing stage and the flowering-filling stage.

Abstract:依据在日光温室条件下的田间试验,研究了水分和氮素水平对豇豆产量和品质的影响,以期筛选较佳水分和氮素控制指标,为豇豆优质高产提供依据。结果表明:同一氮肥处理下,豇豆产量随土壤水分含量增加而显著增加,达到土壤相对含水量(RH)75%~85%时产量最高,豇豆高产较佳的水分和养分组合为:氮肥120 kg/hm2,壤RH为60%~85%。水分对豇豆鲜菜可溶性糖含量影响不明显;在水分充足条件下氮肥能提高豇豆的可溶性糖含量;水分有助于提高豇豆的Vc含量,水分、氮肥适宜豇豆可获得较高的Vc含量。豇豆硝酸盐含随施氮量增加显著增大。在氮素水平为60~120 kg/hm2条件下,水分对豇豆硝酸盐含量影响不明显,在氮素水平为180kg/hm2条件下,水分明显增加豇豆硝酸盐含量。按照蔬菜中硝酸盐含量安全标准,在氮水平为60~120 kg/hm2条件下豇豆的硝酸盐含量均在250 mg/kg以下,达到一级安全标准。氮水平120 kg/hm2是较佳的豇豆安全施肥量。综合考虑水分和氮肥对豇豆安全品质、营养品质以及产量的效应,建议豇豆生产中氮肥用量为120 kg/hm2左右,田间持水量保持在60%~85%。

Abstract:After 10-growth-year alfalfa furrowed,experimentation that include 9 kinds of alfalfa-grain rotation patterns has been carried out in dried area of southern Ningxia during 2003-2005 year.It has been studied that effects of different rotation patterns on third spring wheat yields,soil nutrients,pH values and enzyme activities.The results showed that there are significant differences at above indexes of the third year rotation spring wheat of 9 kinds of alfalfa-grain rotation patterns,organic matter,total N,available N,available K average contents and pH values of 0-60 cm soil layers all decreased,which breadths is 0.05~2.24 g/kg,0.019~0.325 g/kg,0.118~12.280 mg/kg,8.87~166.88 mg/kg and 0.03~0.31,respectively.It has cumulation effect that No.1 and No.2 year rotation grains absorb soil water and nutrients,which decrease by rotation year adds.It is dominating that rotation crops consume soil nutrient at the first rotation year and consumption quantity was different with crop species.When the first rotation crop is spring wheat,consumption of this rotation pattern's soil N and P is the least of all,it is second when it is millet,and it is the most when it is potato.As millet favor to available K,soil available K was use greatly when former stubble grains was millet,it is more little than millet when former stubble grains was potato,and it is the least when spring wheat.Soil organic matter and available P decrease greatly when those three grains rotate with free arrange in groups.In all rotation patterns,potato and millet use greatly soil water than spring wheat,so it lead to soil keep high alkalescence degree.In the alfalfa-grain rotation patterns,grain succession pattern induce to soil urease activity decline,which breath is more great than other patterns'.Potato succession pattern lead to soil Alkaline Phosphatase activity fall,soil Invertase activity of crop succession pattern is more high than others.

Abstract:The effects of Al and F interaction on the soil enzyme of Bai tea and Zhirenzao tea rhizosphere were studied by means of pot culture experiments.Results revealed that Al significantly inhibited urease activity and polyphenoloxidase activity,and the activities of the other eight enzymes were increased significantly under low Al concentration(200 mg/kg),but decreased slightly under higher concentration(400 mg/kg).With the addition of F,polyphenoloxidase activity slightly decreased,and the activities of the others increased at low F concentration(40 mg/kg) and then decreased at higher F concentration(120 mg/kg),but there was no obvious effect on phosphatase or uric acidase.The effect of F on soil enzyme of tea rhizosphere was less significant than that of Al.When Al and F coexisted,interaction of Al and F showed different significant combination effects on enzyme activity,synergistic or antagonistic,which depending on the concentration association of Al and F,the specie of soil enzyme,as well as the variety of tea plant treated.We also found that with the coexistence of 40 mg/kg F and 200 mg/kg Al,almost all of the enzyme activities were stimulated and reached the highest point which indicating that some certain ratio of Al/F was needed for tea plant.In addition,obvious different response of soil enzyme to Al and F stress occurred between Bai tea and Zhirenzao tea rhizosphere,whether the difference had relation with the different tolerance to Al and F remain to probe into further.

Abstract:The soil enzyme activities and nutrients of three types of wetland(Carex lasiocarpa,Calamagrostis angustifolia and island forest wetlands) in Sanjiang Plain were investigated.And the relationship between soil enzyme activity and nutrients and the relationship among enzyme activities were discussed.The results indicated that soil enzyme activity and nutrients differed obviously among different wetlands in Sanjiang Plain.The content of soil organic matter,total nitrogen and available nitrogen were in the order of Carex lasiocarpa wetland>Calamagrostis angustifolia wetland >island forest wetland.And the activities of invertase,urease,amylase,catalase were in the same order.The acid phosphatase activity was in the order of island forest wetland>Carex lasiocarpa wetland>Calamagrostis angustifolia wetland.However,the activity of cellulase was in the order of Carex lasiocarpa wetland>island forest wetland>Carex lasiocarpa wetland.Through Pearson correlative analysis,the activities of urease,amylase,catalase were significant related to soil nutrients.And there were significant correlation among the three enzymes.Therefore,the activities of urease,amylase and catalase were possible to predict the soil nutrients.

Abstract:以土壤、水泥、沙子、秸秆、草炭、纤维素、锯末、糠醛渣、保水剂、控施肥和速效肥为基本原料,按不同比例配制成3种生态护坡基质,探讨了其中微生物的种类和数量以及随时间的动态变化。结果表明:3种生态护坡基质中细菌、放线菌、真菌数量依次为109,108~109,106cfu/g数量级,分别比对照土壤高101,101~102,101个数量级;随时间变化,3种生态护坡基质中细菌数量起初有所下降,之后逐渐增加,最后呈稳定状态,其变化趋势与微生物总数一致,放线菌数量逐渐增加,并对微生物总数贡献提高,而真菌数量逐渐减少,且变化幅度较大;不同处理之间方差分析表明,微生物数量大小顺序为:基质Ⅰ>基质Ⅱ>基质Ⅲ>对照土壤,且除基质Ⅰ与基质Ⅱ之间细菌未达极显著水平和放线菌未达显著水平外,其余均达极显著水平;相关分析表明,氮和磷对微生物影响最明显,且微生物数量与pH值和电导率均呈现一定程度的负相关。

Abstract:通过对2005年和2006年东祁连山高寒草地4种不同草地类型(珠芽蓼草地、禾草草地、沼泽草地、嵩草草地)土壤3大类群微生物(真菌、细菌、放线菌)数量的时空动态进行研究。结果表明:(1)不同空间层次草地土壤3大类群微生物数量变化均较大,0-10 cm土层的数量为10-20 cm土层的1.02~3.89倍;(2)不同植被下土壤3大类微生物数量季节变化各有其自身的特点,年际变化也不一致;(3)不同植被下同一时间草地土壤三大类群微生物总数量差异较大,为0.83×107~4.71×107个/g;(4)三大类微生物中,细菌数量最大,放线菌次之,真菌最小,分别占微生物总数的48.9%~67.69%,32.18%~48.96%和0.08%~0.25%。

Abstract:在海拔2 500,2 700,2 850,3 000 m的草原上利用Li-6400-09土壤呼吸叶室测定仪测定一个生长季节祁连山排露沟流域放牧草原土壤呼吸速率,分析不同环境条件下土壤CO2释放速率对气候和土地利用的反馈作用。辅助测定地面温度(0 cm、最低温度和最高温度)、地下温度(5,10,15,20 cm)、空气温度、土壤含水量。通过2003-2006年的观测结果表明:(1)土壤呼吸速率有明显日变化规律,7:00-14:00逐渐升高,14:00达到最大值,其值为8.92μmol/(m2.s);之后开始逐渐下降,5:00-6:00达最小值,其值为0.37μmol/(m2.s);(2)土壤呼吸速率有显著的季节变化趋势,呈单峰曲线,与温度的季节动态相吻合,出现"低-高-低"变化趋势。(3)放牧直接影响土壤含水量,放牧程度与土壤含水量呈负相关,土壤含水量与土壤呼吸速率呈正相关。重度放牧区土壤含水量>过度放牧区土壤含水量>极度放牧区土壤含水量,且重度放牧区土壤呼吸速率>过度放牧区土壤呼吸速率>极度放牧区土壤呼吸速率。(4)温度是影响土壤呼吸的主要因子,温度与土壤呼吸速率呈正相关,呼吸速率最大值出现在一年温度最高月6-7月,值为8.92μmol/(m2.s);最小值出现在5月,值为0.37μmol/(m2.s),继续降温呼吸速率基本停止。

Abstract:The purification effect and mechanism on polluted water by ecological beds systems of Rumex acetosa Linn were studied and the experiment went on 48 days.The results indicated:The removal rate for total nitrogen and NH 4-N was 92.40% and 97.00%,which are 4.47,1.10 times greater than no plant systems,and the remove for NH 4-N depend on nitration of nitrifying bacteria,on the contrary the remove for NH 4-N of the no plant systems depend on ammonia volatilization.The NO-3-N of Rumex acetosa Linn systems is from high to low,however,the no plant systems is no obvious changes.The remove effect for total phosphorus and COD is 79.17%,86.63% in the end experiment,which had a significantly different with no plant systems.The experimental result demonstrates that the Rumex acetosa Linn is recommended as one species of aquatic vegetation in phytoremediation for polluted water.

Abstract:氮素是作物的营养元素,以及河流主要水质指标之一,也是引起水体污染、水体富营养化的主要因素,对氮污染的控制与研究已经成为水体环境与生态保护工作的重点。通过对浙江省绍兴地区的曹娥江干流上7个取水断面的一周年(12个月)的实地水质监测,分析了曹娥江干流水环境因子(降水量、水温、pH值、溶解氧、浊度、电导率)与水体中总氮(TN)、可溶态氮(DN)、铵态氮(NH4 -N)、硝态氮(NO3--N)的时空变异特征。结果表明:(1)大田作物作业期间的降水会引发农田氮素流失,从而增加水体中的总氮浓度,而大量的降水在引起氮素流失的同时,也可以起到稀释水体中总氮的作用;(2)可溶态氮浓度平均占总氮浓度的74%,可溶态氮对总氮的贡献具有决定性的地位,其在时间上的变化趋势与总氮相一致,在空间上呈现出从上游到下游下降的趋势;(3)在时间上铵态氮的浓度与水体温度呈负相关关系。空间上铵态氮从上游到下游呈现出下降趋势;(4)在时间上硝态氮浓度与水温呈正相关关系,而空间上却没有明显的变化趋势。

Abstract:The study on the chemical fractionation and bioavailability of heavy metals from non-contaminated and sewage-irrigated soils of Sizhuangding in Xinxiang showed that,total Cd,Ni,Zn,Cu and Cr concentrations of non-contaminated soils achieved the national standard for soils,and sewage-irrigated soil Cr concentration achieved the national standard for soil,while Cd,Zn,Ni and Cu concentrations were over the standard,with the average contents being 65.31,1196.64,2799.25,145.78 mg/kg.The average concentrations of Cd,Zn,Ni and Cu were 65.31,19.94,9.33,1.46 times of national standard for soil,respectively.Sequential extraction rusults showed that,Cd was dominated by iron-manganese oxides fraction,with the percentages being 56.84%.Ni was dominated by iron-manganese oxides fraction and residual bound fraction,with the percentage being 37.44% and 39.55%.Zn was dominated by residual bound fraction,with the percentage being 78.24%.Cu was dominated by organic fraction,with the percentages being 57.70%.Cr was dominated by organic fraction and residual bound fraction,with the percentages being 45.50% and 34.18%.Compared with the non-contaminated irrigation soils,percentage of Cd,Ni,Zn,Cu,Cr residual fractions in the contaminated soils reduced,which could increase the heavy metal mobility and bioavailability.For exchangeable fraction and bioavailability of Cd being higher than Zn,Ni,Cu with the percentages being 24.54%,we should pay attention to the mobility and phyto-toxicity of Cd.

Abstract:The soil moisture and water potential of artificial vegetation in the mixed area with water and wind erosion of the Loess Plateau has being measured by the stove method using WP4 Dewpoint Potential Meter.The research analyzed the characters of spatial and temporal distribution and dynamic change of soil moisture from both volume and energy side,calculated the soil water retention curve of different species trees based on real data.The results would provide the necessary theoretical reference for the vegetation construction and ecological water requirement.The result indicated that,with the depth increasing,the soil moisture decreased to stabilization in 0-300 cm soil layer.Soil moisture markedly changed in 0-30 cm soil layers,but soil moisture gradually decreased to stabilization at the 3.00%~5.00% below 30 cm soil layer.Soil moisture was significantly affected by the precipitation and its distribution,and in the observation period soil water reserved 26.7 mm.Soil water potential and soil moisture changed consistently,all correlation coefficients were over 0.95,and the results of soil water retention curve fitting were better.In the high-flow year,rainfall supplied moisture to the soil of shallow layer,but the soil of deep layer was seriously short of moisture.There were dried earth layers in the deep soil layer.It is of great significance to pay more attention to the soil moisture in the special rainfall years.

Abstract:通过对西南喀斯特不同石漠化过程中典型土壤水力特征的分析,研究了土壤水分参数与土壤水分库容特征及其影响因素。结果表明:(1)喀斯特地区土壤水分特征曲线呈先陡后缓的趋势,当土壤水吸力S<300 KPa时,土壤含水量θm下降很快,且陡直,土壤水分释放快,释放量大;当水吸力S超过300 KPa,直至1.5 MPa吸力段时,θm变化平直,土壤水分释放慢,释放量小。(2)未石漠化的荔波森林黑色石灰土表层土壤田间持水量达587.8 g/kg,有效水含量达435.8 g/kg,明显高于其它受到石漠化影响的土壤。土壤容重、孔隙度和有机质含量是影响土壤水分特征参数的主要因素。(3)喀斯特地区土壤较薄,土壤总库容和有效库容较低,是石灰岩地区土壤易发生侵蚀性退化和干旱的重要原因。通透库容占总库容的比例为:未石漠化的荔波原始森林黑色石灰土>潜在石漠化的普定灌丛黑色石灰土、玉米地棕色石灰土>轻度石漠化的荔波玉米地黄红壤,石漠化的发展减弱了土壤抗侵蚀能力。土层厚度、土壤有机质含量、土壤颗粒组成及0.3~0.03 mm孔隙度是影响土壤水分库容的主要因素。

Abstract:In comparison with barren slope,a pilot study of hydrology effect of artificial woodland surface soil in semi-arid low mountainous upland region of western Liaoning province was carried out.The results indicate that soil bulk density is minimum in Vitex negundo forest,it is maximal in P.simonii forest;Soil total porosity,capillary porosity and non-capillary porosity in Vitex negundo forest are maximal,they are minimum in P.ssimonii forest;soil water storage,effective capacity and capillary water holding capacity of surface soil in woodland are higher than barren slope,soil water storage,effective capacity and capillary water holding capacity in Vitex negundo forest are maximal,they are minimum in P.simonii forest,soil water storage range from 701.8~1 328.4 t/hm2,effective capacity range from 41.2~411.6 t/hm2,capillary water holding capacity range from 660.6~916.8 t/hm2;Infiltration capacity of surface soil in woodland is better,steady infiltration rate in Vitex negundo forest is maximal,it is minimum in P.ssimonii forest,steady infiltration rate range from 0.03~6.11mm/min,there is a significant positive correlation between steady infiltration rate and the total porosity,so as steady infiltration rate and non-capillary porosity,there is power function connection between soil infiltration rate and time;According to function of soil and water conservation in woodland surface soil,we can put the following items as such orders: Vitex negundo forest>Prunus sibirica-Vitex negundo mixed>Pinus sylvestnis var.mongolica forest hillclosed and afforested>Larix principis-rupprechtii forest>P.tabulaeformis-Vitex negundo mixed forest>H.rhamnoides forest>P.simonii forest.

Abstract:利用洞庭湖及周围6个水文站有关资料,研究了洞庭湖滩涂和草甸沼泽湿地调蓄水量的功能。结果表明:东洞庭湖滩涂和草甸沼泽湿地调蓄水量81.03×108m3,南洞庭湖59.66×108m3,西洞庭湖21.30×108m3,共计调蓄水量161.99×108m3;湿地蓄水能力随水位高程而变化,但变化速率不一,低水位时随水位升高,湿地蓄水面积和蓄水量缓慢增加,到达一定高度,蓄水面积和蓄水量都迅速增大,再上升到某一高度,蓄水面积增加率急剧下降,蓄水量增加率趋向稳定;枯水期,湿地蓄水的主要服务对象为维护生物多样性和动、植物的生存用水(17.42×108m3),平水期服务主要对象为生产、生活用水(35.60×108m3),汛期的主要服务对象为调蓄洪水(108.97×108m3)。洞庭湖滩涂和草甸沼泽湿地蓄水服务功能有近2/3用在调蓄洪水量上。利用"等效益相关替代法"和"影子价格法"评估了洞庭湖湿地蓄水服务功能价值为31.27×108元。

Abstract:In view of our country northeast half arid area slope farming's plow layer thins year by year.The structure hard and the close plough pan uppers and thickens.Causing the soil water percolation,the ventilation to miss extremely,the soil runoff and the silt corrosion are serious.Moisture content infiltration Influenced seriously.Has using the concentric ring pressed in infiltrates experimental and the open country simulation rainfall experiment.Having studied slope farming in the tied ridging culture,between breaks the plow sole scope according to the pitting difference field earth.The plough pan of slope farming to the moisture content infiltration influencing has analyzed.The result indicated that the plow sole broke partially.The moisture content stable infiltration rate enhances,producing the class time expands,the runoff and the silt reduce obviously.

Abstract:为了探讨CO2浓度增加对干旱荒漠区胡杨气体交换的影响,在塔里木河下游4个不同地下水埋深环境测定胡杨在CO2浓度分别为360,720μmol/mol条件下的光合速率、气孔导度、水分利用效率。结果表明,在地下水埋深4.12 m和4.74 m时,当CO2浓度由360μmol/mol增加到720μmol/mol时,胡杨的气孔导度略有减小;而在地下水埋深5.54 m和7.74 m环境下,CO2浓度的增加明显减小了胡杨的气孔导度。在CO2浓度为360μmol/mol时,胡杨的光合速率随着地下水埋深的增加而减少,然而当CO2浓度增加到720μmol/mol时,胡杨的光合速率不但没有因为地下水埋深的增加而减少,反而却因此而增加。当地下水埋深在4.12 m时,CO2浓度的增加对胡杨的水分利用效率没有产生明显的影响,但是随着地下水埋深近一步增加到4.74 m,5.54 m和7.74m时,胡杨的水分利用效率因CO2浓度的倍增分别增加了69%,18%和66%。地下水埋深最终控制着干旱荒漠区胡杨气体交换对CO2浓度升高的响应。

Abstract:蒋家沟流域内大量泥石流由滑坡引发,在滑坡转化为泥石流的3个过程中,首先是在斜坡体内大范围剪切破坏。在其物源区与沉积区内分布大量砾石土,其强度特征对于蒋家沟泥石流的起动机理以及流域内土壤侵蚀具有重要意义。由于降雨过程中,坡体内砾石土含水率逐渐增大,影响其力学性质特征,加之砾石土颗粒粗大,粗细粒配比和试验尺寸对强度特征有一定的影响。为此,在室内和现场两用大型直剪仪下进行蒋家沟砾石土不同含水率下的直剪强度试验,结果表明,试样在ρd=1.9 g/cm3不同含水率下,剪应力-水平位移关系没有明显峰值,应力-应变曲线为应力硬化型;同一含水率试样在γ=0.02时的剪切模量G0.02随垂直压力增加而增大;含水率7.07%试样各级压力下G0.02最大;φ值与含水率w符合二次函数关系式:φ=-0.471w2 6.7462w 3.9262;试样C值与含水率w符合二次函数关系式:C=-0.7307w2 8.4784w 1.462。

Abstract:According to the non-point source pollution characteristics of sediment-laden river,combining with the pollutant content relation between the river bed sediment and inner drainage area surface soil,advising the non-point source pollution loads estimation method of soil and water loss region in limited data direction and applying the method in Huaxian section of the Weihe River Basin.This method is simple and practicable,the requirement of data is less so the method can be applied for elementary estimation in soil and water loss region.The research shows: The correlation degree between total phosphorus load of non-point source pollution and flood season sediment discharge is highest and is 0.91 in Huaxian section of the Weihe River Basin,the correlation degree between ammonia nitrogen and flood season sediment discharge is 0.78 and the correlation degree between nitrate nitrogen and flood season sediment discharge is 0.77.In high sediment concentration year,the ammonia nitrogen output is 53 304 t,the nitrate nitrogen output is 18 878 t and total phosphorus output is 237 387 t;in natural and low sediment concentration year,the ammonia nitrogen output are respective 26 796 t and 9 204 t,the nitrate nitrogen output are respective 10 444 t and 4 847 t,the total phosphorus output are respective 144 431 t and 82 740 t.